SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4fc23144caa27be8892ee12c8313512d70cadddbd9cbe1c53c570f42aa75fa' 
  AND token = 'U0+3m1PeABFgOXVfTPN2Xd8AwK8q0VSp6e+VPsmCYzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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