SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c77e4b5a2242a70cfb373b99d776c9c71e656cec78cec4d3aeb83e4b22ddc703' 
  AND token = 'dag3yyPjF8P4ofFxL2pWPA/Rvv4ZT65xB0cLulA6itk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}