SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e7c6c0e667fba828744c79112406480135745f786d1137fb0bd015766798964' 
  AND token = 'hyijRXRYuHI1IJrm6+E0xcoSVaqhv2uz3z3mYVdKZnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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