SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41b75ad862bf30862e5930b62fa708f9d7a5e53159abf9733576ece2c8e4a6cc' 
  AND token = 'qM6dcHte/ZSESOvdPkVlt2Bz3fmKYPHOb/HnlNePF+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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