SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a62e4691fcbd0ecd6439583ceaed35542c7f6f87bfeba96e2aedc431458ee9dd' 
  AND token = 'L5gCLRID+a6cCwuanCEMw9HmjtbCThooUrnH88qju2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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