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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4aadd01e53258e1351670dd7fb1dd94357ae294236c9148a6f5c8d2b3eac343' 
  AND token = '18repD1rQsb3fncnki0YrreB2jMaNFBGu/sLHW2HajA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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