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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c90da7dfa7a79b5ec1f3cf0a96e611ae60b24e6a186b3a2b441e7ae9aa1ad57c' 
  AND token = 'tKPvNAINAyUrp5AbswEx3dwCcd/yys3/JIUykv0HPws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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