SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8974e7ea00e65d696f5c1af6770e403bd660fd7f0cf4278ad7e2e7f69ebcb2fe' 
  AND token = 'y5BqIOHMReHJcbvpf2ReYQOhuvKAtO1OLU0Vpu/gSZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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