SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef6c00245d245ad60ff28667e7dafb1852d1ef96a72365f417a92054eea9818' 
  AND token = '2MRpsXvjHPFiLaP3m/ZVj00R9H593Z0imTd+wCEjapg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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