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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceae216f6f8c90d59c9c4b6b90b16aed5853a78476b5c276518e5bece604c771' 
  AND token = 'knjfIoACrIq/cql0s7dPGORvwpVwLiYqCHgHHeP9UHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}