SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df2b2bd5d51d7a23c91244c50be263d4be09e28ba45597b82f8790cff622738' 
  AND token = 'Z/kzf+9iVUVlhlgYScMdGYlbpWORzX0ifzBI4TsaC5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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