SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce7780d9f3dc8a188b25312c22e10dfc76aff2e6de8f754a3d394ab5c658e9d3' 
  AND token = 'BIiT7d+ebZtEBiC0tJizVfocPjPdJWBchKnyvVtleHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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